Limits...
N- and S-doped high surface area carbon derived from soya chunks as scalable and efficient electrocatalysts for oxygen reduction

View Article: PubMed Central - PubMed

ABSTRACT

Highly stable, cost-effective electrocatalysts facilitating oxygen reduction are crucial for the commercialization of membrane-based fuel cell and battery technologies. Herein, we demonstrate that protein-rich soya chunks with a high content of N, S and P atoms are an excellent precursor for heteroatom-doped highly graphitized carbon materials. The materials are nanoporous, with a surface area exceeding 1000 m2 g−1, and they are tunable in doping quantities. These materials exhibit highly efficient catalytic performance toward oxygen reduction reaction (ORR) with an onset potential of −0.045 V and a half-wave potential of −0.211 V (versus a saturated calomel electrode) in a basic medium, which is comparable to commercial Pt catalysts and is better than other recently developed metal-free carbon-based catalysts. These exhibit complete methanol tolerance and a performance degradation of merely ∼5% as compared to ∼14% for a commercial Pt/C catalyst after continuous use for 3000 s at the highest reduction current. We found that the fraction of graphitic N increases at a higher graphitization temperature, leading to the near complete reduction of oxygen. It is believed that due to the easy availability of the precursor and the possibility of genetic engineering to homogeneously control the heteroatom distribution, the synthetic strategy is easily scalable, with further improvement in performance.

No MeSH data available.


Structure of molecules as heteroatoms sources in glycine max: (a) arginine, (b) leucine, (c) lysine, (d) phenylalanine and (e) tryptophan as N sources; (f) cysteine and (g) methionine as S sources; and (h) phytic acid as the P source.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC5036483&req=5

Figure 1: Structure of molecules as heteroatoms sources in glycine max: (a) arginine, (b) leucine, (c) lysine, (d) phenylalanine and (e) tryptophan as N sources; (f) cysteine and (g) methionine as S sources; and (h) phytic acid as the P source.

Mentions: Soya (glycine max) is used as a food ingredient and is widely available as a less-expensive processed food with a high protein content (>50%, carbohydrate content ∼30%). Its constituent molecules, such as cystine and methionine, contain sulphur, while lycine, threonine, leucine, isoleucine, valine, tryptophan, phenylalanine and arginine contain nitrogen bonded to a carbon atom (figure 1). It is also rich in phytic acid with a high phosphorus content. Therefore, we presumed that pyrolysis of soya chunks would lead to a conducting carbon network doped with essential heteroatoms. In this manuscript, we show that soya is a natural precursor to obtain large quantities of an excellent low-cost carbon-based catalyst with a high surface area (∼1000 m2 g−1) for use in a fuel cell cathode. During ORR measurements in basic media, an onset potential of −0.045 V as well as high efficiency with a ∼4 electron reduction pathway was recorded, which is comparable to that of commercial Pt catalysts. It has better long-term stability compared to commercial Pt. Furthermore, it exhibited excellent methanol tolerance, unlike the metal-based catalysts, demonstrating a promising alternative for costly Pt-based electrocatalysts.


N- and S-doped high surface area carbon derived from soya chunks as scalable and efficient electrocatalysts for oxygen reduction
Structure of molecules as heteroatoms sources in glycine max: (a) arginine, (b) leucine, (c) lysine, (d) phenylalanine and (e) tryptophan as N sources; (f) cysteine and (g) methionine as S sources; and (h) phytic acid as the P source.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036483&req=5

Figure 1: Structure of molecules as heteroatoms sources in glycine max: (a) arginine, (b) leucine, (c) lysine, (d) phenylalanine and (e) tryptophan as N sources; (f) cysteine and (g) methionine as S sources; and (h) phytic acid as the P source.
Mentions: Soya (glycine max) is used as a food ingredient and is widely available as a less-expensive processed food with a high protein content (>50%, carbohydrate content ∼30%). Its constituent molecules, such as cystine and methionine, contain sulphur, while lycine, threonine, leucine, isoleucine, valine, tryptophan, phenylalanine and arginine contain nitrogen bonded to a carbon atom (figure 1). It is also rich in phytic acid with a high phosphorus content. Therefore, we presumed that pyrolysis of soya chunks would lead to a conducting carbon network doped with essential heteroatoms. In this manuscript, we show that soya is a natural precursor to obtain large quantities of an excellent low-cost carbon-based catalyst with a high surface area (∼1000 m2 g−1) for use in a fuel cell cathode. During ORR measurements in basic media, an onset potential of −0.045 V as well as high efficiency with a ∼4 electron reduction pathway was recorded, which is comparable to that of commercial Pt catalysts. It has better long-term stability compared to commercial Pt. Furthermore, it exhibited excellent methanol tolerance, unlike the metal-based catalysts, demonstrating a promising alternative for costly Pt-based electrocatalysts.

View Article: PubMed Central - PubMed

ABSTRACT

Highly stable, cost-effective electrocatalysts facilitating oxygen reduction are crucial for the commercialization of membrane-based fuel cell and battery technologies. Herein, we demonstrate that protein-rich soya chunks with a high content of N, S and P atoms are an excellent precursor for heteroatom-doped highly graphitized carbon materials. The materials are nanoporous, with a surface area exceeding 1000 m2 g−1, and they are tunable in doping quantities. These materials exhibit highly efficient catalytic performance toward oxygen reduction reaction (ORR) with an onset potential of −0.045 V and a half-wave potential of −0.211 V (versus a saturated calomel electrode) in a basic medium, which is comparable to commercial Pt catalysts and is better than other recently developed metal-free carbon-based catalysts. These exhibit complete methanol tolerance and a performance degradation of merely ∼5% as compared to ∼14% for a commercial Pt/C catalyst after continuous use for 3000 s at the highest reduction current. We found that the fraction of graphitic N increases at a higher graphitization temperature, leading to the near complete reduction of oxygen. It is believed that due to the easy availability of the precursor and the possibility of genetic engineering to homogeneously control the heteroatom distribution, the synthetic strategy is easily scalable, with further improvement in performance.

No MeSH data available.